Child proof bottle cap

ABSTRACT

A screw-top closure for bottles is provided which must be turned upside down to be unscrewed. When the right way up the closure which is constructed so as to fit a standard glass bottle and is complete in itself, requiring no modification or addition to the bottle or its screw-top - can be screwed up but can be turned endlessly without unscrewing. This is achieved by a two part construction having an inner shell with the screw thread on it and an outer shell for manual operation. The two are connected together by a ball bearing; the outer shell has an internal land which drives the ball bearing. It is only when the bottle is upside down and the outer shell is rotated anti-clockwise that the ball bearing finds a land to drive the inner screw thread containing shell.

United States Patent [191 Danner et al.

[111 3,734,330 51 May 22,1973

{54] CHILD PROOF BOTTLE CAP [22] Filed: Nov. 22, 1971 [21] Appl. No.: 200,918

[30] Foreign Application Priority Data Sept. 24, 1971 Canada ..123,624

[52] U.S. Cl ..2l5/9 [51] Int. Cl. ..B65d 55/02 [58] Field of Search ..2l5/9, 46, 43 A [56] References Cited UNITED STATES PATENTS 2,499,765 3/1950 MacLaren ..2l5/9 UX 3,620,398 11/1971 Andersen ..215/9 Primary Examiner-George T. Hall Attorney-George H. Spencer et a1.

[57] ABSTRACT A screw-top closure for bottles is provided which must be turned upside down to be unscrewed. When the right way up the closure which is constructed so as to fit a standard glass bottle and is complete in itself, requiring no modification or addition to the bottle or its screw-top can be screwed up but can be. turned endlessly without unscrewing. This is achieved by a two part construction having an inner shell with the screw thread on it and an outer shell for manual operation. The two are connected together by a ball bearing; the outer shell has an internal land which drives the ball bearing. It is only when the bottle is upside down and the outer shell is rotated anti-clockwise that the ball bearing finds a land to drive the inner screw thread containing shell.

5 Claims, 5 Drawing Figures Patented May 22, 1973 2 Sheets-Sheet l Patented May 22, 1973 2 Sheets-Sheet 2 This invention relates to the problem of screw-top closures for containers which may hold tablets harmful to young children; such closures must be operated easily by an adult but must defeat the attempts of young children to open them.

It has heretofore been a problem to provide such a closure which can be sold separately from, and which will fit, a screw-top bottle without requiring modification or addition to the bottle itself. Accordingly, one object of this invention is to provide such a closure for any screw-top bottle or container so that the closure is complete in itself.

The invention comprises a closure made in two parts or members with a gravity operated connection between the two parts; theclosure is complete in itself, and is inexpensive.

Of course, gravity operated closures are known, a

good example being seen in US. Pat. No. 3,410,434

but such a construction requires modifications to the container and besides which the solution is somewhat complex; thus, strictly speaking, it requires more than two special major parts.

Reference to the drawings show a screw-on closure which illustrates the invention by way of example as will be understood after reading the following description.

In the drawings:

FIG. 1 shows the closure in elevation as it appears on a bottle, but part is broken away to show a section.

FIG. 2 shows a horizontal section of one major component.

FIG. 3 shows a vertical section through the other major component.

FIG. 4 shows in a perspective cut-away view how normal anticlockwise turning will fail to unscrew the composite cap when it is the right way up; the bottle has been omitted for clarity.

FIG. 5 shows also in a perspective cut-away view how anticlockwise turning will positively unscrew the composite cap when the bottle is turned upside down; the bottle has been omitted again so as not to confuse the drawing.

In FIG. 1, a bottle 2 has the usual screw threaded opening and access to the contents is prevented by composite closure 4.

This composite closure 4 comprises a first major component 6, called the outer member; within this is a second major component 8 called the inner member, which carries the threads7 for engaging the bottle. These are held together by an inwardly projecting lip 9 integral with outer cap 6. In addition a gravity operated connecting member which is of such a shape that it can roll freely (such as a small steel ball of the type found in ball bearings) is accommodated between the outer cap 6 and the inner cover 8. As will be explained below, the internal configuration of these two components is such that when the bottle is the right way up the outer cap 6 will rotate about the inner cover without driving it when an attempt is made to remove the closure by unscrewing.

Referring to FIGS. 1, 2 and 3 of the drawings it will be seen that the connecting member, or ball bearing, 10 is trapped in a longitudinal recess 12 of approximately semi-circular section in central pillar l4 integral with outer cap 6; the ball bearing can roll along the inner surfaces 16 of inner cover 8 when the outer cap is turned.

Now referring to FIG. 4 it will be understood. that if an attempt is made tounscrew the closure by gripping it on the knurled surface 18 of the outer cap 6 and twisting it anti-clockwise nothing will happen if thebottle is the usual'way up. The ball driven by the forward going face 19 of recess 12 in the central pillar 14, can travel endlessly around the track 20. The purpose of the discontinuity 26 in the track 20 will be explained below. Arrows A and B" indicate upward sense and unscrewing motions respectively.

As can be seen in FIG. 5 (note the apparent-not-realreversal of unscrewing twist B due to inversion) when the bottle is inverted the ball falls onto track 22 but now when it is driven, again in an anti-clockwise direction, it can only turn a maximum of one revolution before being trapped between the abutment formed by the forward going face 19 of recess 12 and the face 24; the forward going face 19 cannot be seen in FIG. 5 because it is hidden by the leading edge 21 of recess 12.

Once the ball is trapped it will be understood that the bottle can be returned to the upright position if the unscrewing force is maintained, because friction will prevent it from dropping into track 22.

Now the reason for providing a face 26 in track 20 is to enable the closure to be screwed onto the bottle in a normal fashion. This makes it difficult for a child to understand that it will not unscrew in the same manner and it is a very inexpensive way indeed of driving inner cover 8 by outer cap 6. However, between these two components any other types of connection which will drive in a clockwise sense, but not anti-clockwise could be used. Such sprag drives and unidirectional clutches are well known.

We prefer to make the ramp reasonably short so that increased height of the track corresponding to the depth of the face is achieved in V4 of a revolution; the remainder of the track is in one transverse plane.

We also prefer to make both tracks the same for symmetrical reasons. It is true that this means that the closure we have illustrated cannot be screwed up when the bottle is upside down, but this is so little of a disadvantage that it will pass unnoticed. It is also possible to eliminate track 22 entirely and provide a series of abutment faces 24 by substituting, for the helix-andcylinder end face which forms track 22, a number of castellations between which there is a gap wide enough to accommodate the ball bearing, 10. Such castellations could be most easily visualized by referring to FIG. 5. It will also be understood that when we talk about upside down or inverted these are illustrative, and extreme conditions, and a slight downward tilt (such as is necessary to shake the contents of a half empty bottle towards the mouth) will normally be enoughto jog the ball into the driving position so that cap rotation will trap the ball between the faces which form the abutment.

While there has been shown and described what is at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention as defined by the appended claims.

We claim:

1. A safety screw-top closure consisting essentially of an inner member having a screw thread adapted to receive the top of a container;

an outer member for manual operation and surrounding said inner member and capable of rotation thereabout;

a gravity operated connector accommodated between said outer and inner members; means on said inner and outer members for connecting said members together through the gravity operated connector when the outer member is driven anti-clockwise and when the closure is inverted but not when the closure is the right way up and the outer member is driven anti-clockwise; and

means to connect the two members for clockwise rotation of the inner member when the closure is the right way up.

2. A safety screw-top closure as claimed in claim 1 in which the gravity operated connector is a small freely rolling ball.

3. A safety screw-top closure as claimed in claim 2, in which the means on said inner and outer members for connecting the two members together for inverted anti-clockwise rotation but not otherwise comprises:

abutment means having a forward going face upon the outer member when rotated anti-clockwise and a corresponding opposing face on the inner member so that the ball may be trapped between faces when the closure is inverted; and

the inner and outer members together cooperate to provide a cavity below the abutment which will permit the ball to travel anti-clockwise round the inner member when the closure is the right way up.

4. A closure as claimed in claim 3 in which the means to connect the two members together for clockwise rotation of the inner member comprise:

abutment means having a forward going face on said outer member when rotated clockwise and a corresponding face on the inner member opposing the forward going face on said outer member, both faces being below the general level of the cavity so that the ball will drop into engagement with both faces so that clockwise rotation of the outer cover will force clockwise rotation of the inner cover when the closure is the right way up.

5. A closure as claimed in claim 4 in which the abutment with the forward going face when the outer member is rotated clockwise and the abutment with the forward going face when the outer member is rotated anticlockwise is provided by. a single groove. 

1. A safety screw-top closure consisting essentially of an inner member having a screw thread adapted to receive the top of a container; an outer member for manual operation and surrounding said inner member and capable of rotation thereabout; A gravity operated connector accommodated between said outer and inner members; means on said inner and outer members for connecting said members together through the gravity operated connector when the outer member is driven anti-clockwise and when the closure is inverted but not when the closure is the right way up and the outer member is driven anti-clockwise; and means to connect the two members for clockwise rotation of the inner member when the closure is the right way up.
 2. A safety screw-top closure as claimed in claim 1 in which the gravity operated connector is a small freely rolling ball.
 3. A safety screw-top closure as claimed in claim 2, in which the means on said inner and outer members for connecting the two members together for inverted anti-clockwise rotation but not otherwise comprises: abutment means having a forward going face upon the outer member when rotated anti-clockwise and a corresponding opposing face on the inner member so that the ball may be trapped between faces when the closure is inverted; and the inner and outer members together cooperate to provide a cavity below the abutment which will permit the ball to travel anti-clockwise round the inner member when the closure is the right way up.
 4. A closure as claimed in claim 3 in which the means to connect the two members together for clockwise rotation of the inner member comprise: abutment means having a forward going face on said outer member when rotated clockwise and a corresponding face on the inner member opposing the forward going face on said outer member, both faces being below the general level of the cavity so that the ball will drop into engagement with both faces so that clockwise rotation of the outer cover will force clockwise rotation of the inner cover when the closure is the right way up.
 5. A closure as claimed in claim 4 in which the abutment with the forward going face when the outer member is rotated clockwise and the abutment with the forward going face when the outer member is rotated anti-clockwise is provided by a single groove. 